This invention relates generally to well structures for hybrid optical waveguides.
An optical waveguide is a structure that conveys an optical light signal. Conventionally, an optical waveguide may include a substrate and a core encased within an upper and lower cladding. The bulk of the light signal typically travels within the core along the axis of the waveguide structure.
In order to access the core, a well may be formed through the upper cladding. This well may be formed by etching the upper cladding. Sometimes such etching does not completely expose the core of the waveguide, resulting in reduced access to the light signal. In other cases, the core of the waveguide might not only be exposed but it may be damaged by the etching process, resulting in reduced transmission of the light signal.
After the well is formed, the well may be filled with a polymer. If the well is not appropriately formed, voids may be formed within the well where the polymer cannot completely fill the well, also resulting in reduced transmission of the light signal.
Thus, there is a need to form wells for accessing optical cores in hybrid optical circuits that are less prone to forming voids or bubbles or cuts or other damage to the core itself.